Caleb,
The chances are 95% and there is plenty to be concerned about.

but...this is like going to a car forum and posting that you bought a car, no idea what kind of car, how old it is, or if it was ever serviced and asking if it was going to break down in the next year. Any response you received would be absolutely worthless.

: Good day watch lovers,

: My situation is this: I am a complete, absolute, no-nothing newbie
: when it comes to buying vintage watches. Yesterday however, I
: was at a vintage/second-hand market and came across a beautiful
: timepiece which I would very much like to buy. Forgive me, but I
: am not concerned about its value or brand - I am only concerned
: about its functionality. I am told by the seller that it's
: mechanical, and the only thing to affirm this is that the hand
: didn't tick, but rolled.

: So, if I were to buy this, what are the chances that it would cease
: to work, perhaps in a week, or a month, or a year from now? What
: is there to be cautious of when buying 'vintage' or second-hand
: watches, aside from landing a fake?

: Thank you very much and have a nice day.